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Pin Hole Issue after Reflow Soldering - Passive Components

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Hi , We are having Pin hole issues on the passive locati... - Dec 25, 2017 by Arjun K S  

#79524

Pin Hole Issue after Reflow Soldering - Passive Components | 25 December, 2017

Hi ,

We are having Pin hole issues on the passive locations in the board after the SMT reflow process.

Details: PCB surface Finish : ENIG . Solder paste : Alpha OM338 – M13 / Indium SMQ92J Location : Its Random and more on passive components. { 0402 to 1210 package ( in inches ) } Inspection : Magnification ( 10 x )

Trials Done: a)Over baking around 20 hr. Use immediately in line after baking. b)Baking for 10 hr and immediately moving to the desiccator. Taking out the boards from the desiccator on hourly requirement basis. c)Profile was one of the suspect and tried with different profiles. ( RTS, RSS , Long soak ( 100 to 150 Deg C for 90 – 120 sec

Based on all these trials which we performed , we didn't have any improvements. Pls can you help in giving feedback and solutions to eliminating this issue.

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#79531

Pin Hole Issue after Reflow Soldering - Passive Components | 28 December, 2017

Pictures of your issues would help us to help you.

Pin holes/blow holes are generally caused by either moisture or flux volatiles/organics. Since you've virtually eliminated moisture, it might be time to look at your paste/flux.

You can call either Alpha or Indium, and get help from their application engineers. That'll probably be your best bet, as you describe the issue as "random".

You could also try a different paste, since you've already worked on the profiles for this paste.

But, the most important question you can ask is...is this acceptable per IPC? IPC610 allows pinholes/blowholes in all three classes (although as a process indicator in 2 and 3), unless the hole reduces the solder connection below minimum requirements.

In the end, you may be chasing a process limitation on that particular assembly that you don't need to change.

cheers, ..rob

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#79689

Pin Hole Issue after Reflow Soldering - Passive Components | 1 February, 2018

Hi Rob,

Thanks for your reply. Our customer don't need any pin hole in his board.

Attached is the image for your reference.

The issue is minimized for us with hot profile ( 80 - 100 sec in between 170 to 180 deg C ) For leaded paste.

Lead free paste is still a concern.

Regards, Ameenulla khan

Attachments:

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#79695

Pin Hole Issue after Reflow Soldering - Passive Components | 1 February, 2018

When you talk about baking, I get the impression that you're talking about boards. Are you components dry also?

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#79701

Pin Hole Issue after Reflow Soldering - Passive Components | 2 February, 2018

Hi Davef,

Yes we have tried few component for cold baking for around 7 days around 50 to 60 deg C.

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#79748

Pin Hole Issue after Reflow Soldering - Passive Components | 9 February, 2018

Pin holes in the solder joints on various devices can be an indicator of something amiss with the solder paste itself. Solder paste storage may be a concern. Do you possibly have someone putting paste back in the refrigerator after use? Are you trying to accelerate bringing the paste from "cold to ambient?" Both of these behaviors can introduce water into your solder paste system.

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#79749

Pin Hole Issue after Reflow Soldering - Passive Components | 9 February, 2018

Hi Justin,

The solder paste we are monitoring well. And there is thawing machine to make sure solder paste is not opened early, before it reaches its ambient temperature.

we have got a suggestion that , it might be from PCB enig surface finish. Might be some solvents entrapped during pcb surface finish process.

your valuable feedback on it. And any other probable root cause or any suggestions please.

Regards, Ameen

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#79751

Pin Hole Issue after Reflow Soldering - Passive Components | 9 February, 2018

Can you share the oven profile? For me it looks like the profile has fast ramp up and short TAL period. How many zones the oven have?

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#79762

Pin Hole Issue after Reflow Soldering - Passive Components | 13 February, 2018

Hi,

We are using 10+2 reflow oven ( BTU Pyramax 150 ).

We have tried with short TAL ( RTS profile too ).

As of Now we are using the attached profile, which has given us lot better results. But the issue is not eliminated.

Thanks

Attachments:

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#79764

Pin Hole Issue after Reflow Soldering - Passive Components | 13 February, 2018

Attached is one more profile we have tried with high reflow time. The issue with before and this profile is reduced a lot. But not eliminated.

Attachments:

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#79765

Pin Hole Issue after Reflow Soldering - Passive Components | 13 February, 2018

Your profile reflow temps are too low. Omnix338 has a melting temp of 217-221C. Your right on the edge, and your soak temps should be closer to 150 than 180C. Bottom line too high a soak, too low a reflow. Take it or leave it.1874

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#79766

Pin Hole Issue after Reflow Soldering - Passive Components | 13 February, 2018

I am totally with SweetOldBob on this one. Contamination or voids can also help to boost this defect, but considering that you are probably entirely burning off your flux in the soak zone, you might be getting oxidation on your pads and actually get more voids.

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#79767

Pin Hole Issue after Reflow Soldering - Passive Components | 14 February, 2018

Hi Evitmov,

Thanks for your valuable suggestion.

we have used RTS profile. And profiles with an average soak and reflow time.:(

Those profile didn't help us so much.

It at later stage we have adopted to this hot soak profile.

There is one particular part number capacitor component, we have high defect rate.

we are planning to send the component for cross section analysis.

Any suggestion what we can ask in the report

Regards, Ameen.

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#79768

Pin Hole Issue after Reflow Soldering - Passive Components | 14 February, 2018

Hi Sweetoldbob,

Thanks.

We are using SMQ92J solder paste ( Sn63/Pb37 ). We are on higher side of reflow time for leaded paste.

Regards, Ameen

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#79769

Pin Hole Issue after Reflow Soldering - Passive Components | 14 February, 2018

The profile I have shared is for SMQ92J leaded solder paste

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#79772

Pin Hole Issue after Reflow Soldering - Passive Components | 14 February, 2018

Well it looks like you answered you own question. Why would you send the component out for cross section. Why wouldn't you try a different manufacture, assuming you have already used different date codes on this supplier. Is your company contract manufacturing or OEM?

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#79773

Pin Hole Issue after Reflow Soldering - Passive Components | 14 February, 2018

Its Contract manufacturing BOB.

we need to prove component have a problem. If we need to change the manufacturer approved by customer

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#79774

Pin Hole Issue after Reflow Soldering - Passive Components | 14 February, 2018

Ameen Now I'm feeling sorry for you. If all the other components on the assembly have good solderability you have already proven the component is the problem. I spent 27 years in contract manufacturing and been in this situation many times. If your customer will not work with you and let you try another component manufacturer, you do not have a working relation with this customer. I would suspect the customer is buying the cheapest components available, possibly from brokers. You will find a lot of customers out there that have no idea of the requirements for successful manufacturing processes for their design or assembly.You can't make a silk purse out of a sows ear, and Garbage IN is Garbage Out. I can only wish you luck in this situation. Good Luck

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#79793

Pin Hole Issue after Reflow Soldering - Passive Components | 15 February, 2018

Thanks for the wishes BOB.

I am into process engineering. We don't contact the customer. SMT Line support.

Customer might approve also. But our own quality team says its profile issues :(.

Will see.what more can be done from our side.

Thanks, Ameen

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